Large planar surfaces, such as the walls of glass-walled buildings, are typically washed by workers in platforms suspended from the top of the building by an assembly of ropes and pulleys. The workers use a means, such as mops, to wet the surface and remove any dust or debris adhering to the surface. A squeegee is then passed over the surface to remove any excess water. The platform is then moved, typically downward, to an unwashed area of the building and the process is repeated.
This method has many drawbacks. First, it can be extremely unsafe for workers on the suspended platform. Also, the process is slow because the workers can only clean an area within reach of the platform at each platform location. Moreover, this method is not particularly well adapted for use on buildings with inclined or declined surfaces because the workers will likely have difficulty maintaining their balance on a tilted platform and the weight of the platform and the workers pressing on the surface may damage the surface.
It can be seen that there is a need in the art for a method and device for cleaning planar surfaces wherein the device is unmanned, can clean a large area in an expedient manner, and can be used for vertical, inclined, or declined surfaces.